package com.mouchina.base.utils;

import java.math.BigInteger;


/**
 * This class provides convenient functions to convert hex string to byte array and vice versa.
 * @author 99bill
 *
 */
public class HexUtil
{
    private HexUtil(  )
    {
    }

    /**
     * Converts a byte array to hex string.
     *
     * @param b -
     *            the input byte array
     * @return hex string representation of b.
     */
    
    public static String binary(byte[] bytes, int radix){  
        return new BigInteger(1, bytes).toString(radix);// 这里的1代表正数  
    }  
    
    
    public static String toHexString( byte[] b )
    {
        StringBuffer sb = new StringBuffer(  );

        for ( int i = 0; i < b.length; i++ )
        {
            sb.append( HexUtil.HEX_CHARS.charAt( b[i] >>> 4 & 0x0F ) );
            sb.append( HexUtil.HEX_CHARS.charAt( b[i] & 0x0F ) );
        }

        return sb.toString(  );
    }

    /**
     * Converts a hex string into a byte array.
     *
     * @param s -
     *            string to be converted
     * @return byte array converted from s
     */
    public static byte[] toByteArray( String s )
    {
        byte[] buf = new byte[s.length(  ) / 2];
        int j = 0;

        for ( int i = 0; i < buf.length; i++ )
        {
            buf[i] =
                (byte) ( ( Character.digit( s.charAt( j++ ),
                                            16 ) << 4 ) | Character.digit( s.charAt( j++ ),
                                                                           16 ) );
        }

        return buf;
    }
    
    
    private static final String HEX_CHARS = "0123456789abcdef";
}
